title: Radiotherapy in langerhans cell histiocytosis - a rare indication in a rare disease.
abstract: BACKGROUND
  Langerhans Cell Histiocytosis (LCH) represents a rare benign disorder, previously designated as "Histiocytosis X", "Type II Histiocytosis" or "Langerhans Cell Granulomatosis". Clinical presentation includes osteolysis, ulcerations of skin and soft tissues but also involvement of the CNS is described.Because treatment concepts are not well defined the German Cooperative Group on Radiotherapy for Benign Diseases performed a retrospective analysis.
  
  
  METHODS
  Eight closely cooperating centres collected patients' data of the past 45 years. As study endpoints disease free survival, recurrent disease, death and therapy related side effects were defined.
  
  
  RESULTS
  A total of 80 patients with histologically proven LCH were irradiated within the past 45 years. According to the LCH classification of Greenberger et al. 37 patients had stage Ia, 21 patients stage Ib, 13 patients stage II and 9 patients stage IIIb and the median age was 29 years. The median Follow up was 54 months (range 9-134 months). A total of 39 patients had a surgical intervention and 23 patients a chemotherapy regimen.Radiation treatment was carried out with a median total dose of 15 Gy (range 3-50.4 Gy). The median single fraction was 2 Gy (range 1.8-3 Gy).Overall, 77% patients achieved a complete remission and 12.5% achieved a partial remission. The long-term control rate reached 80%. Within an actuarial overall 5-year survival of 90% no radiogenic side and late effects ≥EORTC/RTOG II° were observed.
  
  
  CONCLUSIONS
  In the present study a large collective of irradiated patients was analysed. Radiotherapy (RT) is a very effective and safe treatment option and even low RT doses show sufficient local control.
authors.affiliation: Klinik für Strahlentherapie und Radioonkologie, Franziskus Hospital, Bielefeld, Germany. strahlenklinik@web.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Kriz
authors.forename: Hans Theodor
authors.initials: HT
authors.lastname: Eich
authors.forename: Frank
authors.initials: F
authors.lastname: Bruns
authors.forename: Reinhard
authors.initials: R
authors.lastname: Heyd
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schäfer
authors.forename: Uwe
authors.initials: U
authors.lastname: Haverkamp
authors.forename: Jens
authors.initials: J
authors.lastname: Büntzel
authors.forename: Heinrich
authors.initials: H
authors.lastname: Seegenschmiedt
authors.forename: Oliver
authors.initials: O
authors.lastname: Micke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult